1. Field of the Invention
The present invention relates to a lubricating system for an internal combustion engine in which lubricating oil dropping to and dwelling in a bottom portion of a crankcase is fed to a lubricating oil tank by a recovery pump and the lubricating oil is supplied from the lubricating oil tank to individual portions of the internal combustion engine. The lubricating system includes an overflow oil passage through which the lubricating oil that flows over from the lubricating oil tank is led to a suction port of the recovery pump.
2. Description of Background Art
A lubricating system for an internal combustion engine is know, as shown in FIG. 35, wherein lubricating oil dropping to and dwelling in a crankcase bottom portion 03 after lubricating respective portions 02 of an internal combustion engine is passed through an oil cooler 04, thereby being cooled, and then fed to a lubricating oil tank 05 by a recovery pump 01. The lubricating oil is supplied to the respective portions 02 of the internal combustion engine requiring lubrication and cooling through an oil filter 07 by a supply pump 06. See Japanese Patent Laid-open No. 2001-73736.
In the conventional lubricating system for an internal combustion engine shown in FIG. 35, lubricating oil filling a lubricating oil tank 05 flows over the upper edge of a partition wall 08 partitioning a bottom portion of a crankcase 03 and the lubricating oil tank 05 from each other, back into the crankcase 03, and is permitted to dwell in the crankcase 03. Therefore, the lubricating oil dwelling in the crankcase 03 is stirred by the crankshaft (not shown) and the like in the crankcase 03. As a result, power loss with respect to the internal combustion engine is increased, generation of mist of the lubricating oil becomes conspicuous, and it may take a long time for the lubricating oil to drop to the bottom portion of the crankcase 03. Therefore, it has been necessary to take into account the height of the upper edge of the partition wall 08 and the positional relationship between the partition wall 08 and the crankshaft, etc. See, Japanese Patent Laid-open No. 2001-73736 (paragraphs [0018] and [0027] in “Detailed Description of the Invention”, and FIGS. 4 and 9)